<p>Access to species occurrence records is at the core of the GBIF Data Portal.  The functions provided by the <strong>Occurrence Search</strong> page provide the ability to perform complex searches in order to explore and locate records of interest.</p>

<p>Click on <a href="../occurrence/">OCCURRENCES</a> at the top of any page in the Data Portal to access the <strong>Occurrence Search</strong> page.  Many other pages in the portal provide links to this page and set some initial search filter.  For example, the "Explore occurrences" link from a species' <strong>Overview Page</strong> opens the <strong>Occurrence Search</strong> to find records for that species.</p>  

<h5>Using Search Filters</h5>

<p>However the Occurrence Search page is reached, it is always possible to modify a search by adding or removing search filters.  Adding filters restricts the occurrence records returned to only those that match the criteria specified by the filter(s).  For example, a filter can be applied to limit results to plants in the family Poaceae and then a second filter to further restrict results to records from South Africa.  As more filters are added they refine the search and reduce the range of matching records.</p>  

<p>As a refined search is being constructed, a list of filters in effect is displayed in the upper right area of the page.  A filter can be removed from the list by clicking on the "minus" symbol to the right of the filter.</p>

<p>If a filter category is applied twice (e.g. Scientific name is <em>Panthera leo</em> and Scientific name is <em>Panthera tigris</em>), the portal will treat them as alternatives and therefore will return records that match either (that is, the search will be for <em>Panthera leo</em> OR <em>Panthera tigris</em>).</p>

<p>A list of all the filter categories available can be found below the step-by-step guide.</p>

<h5>Step-by-step guide</h5>

<ol type="1"><li> Select <a href="../occurrence/">OCCURRENCES</a> at the top of any page to open the <strong>Occurrence Search</strong> page.
</li><li> Select a filter category (Scientific name, Classification, Country, etc.) from the drop down menu under "Add search filter".  The portal will automatically provide suitable fields for specifying the value for the filter.  

</li><li> Set the filter by clicking  "Add filter".  This choice is then displayed as part of the search definition under "Your current search" in the upper right of the page.
</li><li> When all desired filters have been set, click on "Search" at the bottom of the list of filters that are in effect.
</li><li> The portal will return an indication of the number of records that match the search (exact numbers for small result sets, otherwise an indication that the count exceeds 1000 records) and will display some sample results (up to five records).  
</li><li> At this point, you can change or refine the search and issue it again, or begin using the results.  The portal displays a set of possible actions:   
<ol type="a"><li> View records on a map - display the results of the search as a map, which can be explored further by zooming in to different areas.  See <a href="maps">Maps in the GBIF portal</a> for more information on using these maps.
</li><li> View records as a table - page through the results with the opportunity to open up the <strong>Occurrence Detail</strong> view for any occurrence record (with full details from the record, a map showing the location and links to additional actions, see <a href="detail">Viewing details of an occurrence record</a>).

</li><li> Download results - download the search results as XML or as a comma-delimited file.
</li><li> Specify - Choose to view only those records from a particular country, data publisher or dataset.
</li><li> List -  the species resulting from the search.</li></ol></li></ol>

<h5>Available Filter Categories</h5>

<ul><li><strong> Scientific name</strong> - enter a scientific name (or part of a name) and choose between "is" and "is like".  This filter will return any records that have a matching name given for the identification of the organism, regardless of how the organism is classified.
</li><li><strong> Classification</strong> - select a species or group of organisms from the classification tree.  This filter will return records for any species within the selected part of the tree.

</li><li><strong> Country</strong> - select a country from the pick list.  This filter will return records from the country identified, whether or not they contain coordinates (but note that adding a coordinate filter (Bounding box, Latitude or Longitude) will limit the results to georeferenced records. 
</li><li><strong> Region</strong> - select a geographic region from the pick list.  This filter will return records from all countries in the selected continent, oceanic area, etc.
</li><li><strong>Host country</strong> - select a country from the pick list.  This filter will return records that are being shared by data publishers in that country.
</li><li><strong> Bounding box</strong> - use the map to select a rectangle defined using latitudes and longitudes.  This filter will return only georeferenced records within the given rectangle.
</li><li><strong> Latitude</strong> - enter a latitude and choose between "is", "greater than" and "less than".  This filter will return only georeferenced records that match the selection.

</li><li><strong> Longitude</strong> - enter a longitude and choose between "is", "greater than" and "less than".  This filter will return only georeferenced records that match the selection.
</li><li><strong> Coordinate status</strong> - select "includes coordinates" to filter out those records that are not georeferenced; alternatively, select "does not include coordinates" to exclude georeferenced records.  To see all records, do not use this filter.
</li><li><strong> Coordinate issues</strong> - select "issues detected" to identify records with coordinates that may be doubtful; otherwise, select "issues not detected"
</li><li><strong> Provider</strong> - select a data publisher from the pick list.  This filter will return records from the specified publisher.
</li><li><strong> Dataset</strong> - select a data network or a data publisher from the first pick list, and then a dataset from the second pick list.  This filter will return records from the selected dataset.

</li><li><strong> Occurrence date</strong> - enter a start date and either enter an end date or select "use specific date".  This filter will return records occurring on the specified date or in the specified date range.
</li><li><strong> Year</strong> - select a year and either "is", "before" or "after".  The filter will return records from the year(s) that match the selection.
</li><li><strong> Month</strong> - select a month from the pick list.  The filter will return records from the specified month, regardless of year.
</li><li><strong> Institution code</strong> - enter an institution code and "is" or "is like".  The filter will return records with the specified institution code.
</li><li><strong> Collection code</strong> - enter an collection code and "is" or "is like".  The filter will return records with the specified collection code.

</li><li><strong> Catalogue number</strong> - enter an catalogue number and "is" or "is like".  The filter will return records with the specified catalogue number.
</li><li><strong> Basis of record</strong> - select a basis of record (specimen, observation, living, germplasm, fossil) from the pick list.  The filter will return records that are based on the selected type of object or observation.</li></ul>
